public function updateSupervision()
 {
     $data = array('supervisor_id' => $this->input->post('txtSupervisor'), 'employee_id' => $this->input->post('txtEmployee'), 'assigned_date' => date('Y-m-d'));
     if (Emp_supervision::create($data)) {
         $this->session->set_userdata('edited', 1);
         Audit_trail_model::auditSupervision($data);
         redirect("ems/supervisions");
     }
 }